I went strict carnivore last winter for around 3 to 4 months eating red meat, organ meat (mostly livers) and pork bacon. I fell of the wagon during a skiing vacation (not because of the skiing effort itself though, that went great) but I plan to start again in a couple of days. I did not find any issue in the lack of variety, in fact I enjoyed the ease of preparation and grocery shopping. Health advantages included weight loss of around 10kgs/22 pounds (slimming 10cm/4inches in the abdomen area), improved psoriasis, improved sleep quality as well as a reduced amount of sleep needed (I started waking after six hours of sleep completely refreshed, instead of usual seven and a half), no more bleeding gums or tooth aches/sensitivities of any kind, not a single case of heartburn or any other digestive discomfort, improved focus and general sense of well being.
Histamine intolerances can be a problem on this way of eating, I found that I did not tolerate slow cooked meats very well which I did not have an issue with at all on a regular diet (did not notice as much of an issue with minced/hamburger meat, as I luckily had a supply of very fresh source). This issue would probably improve over time.
From reading other people's experiences on various facebook/reddit groups and listening to various podcasts I am pretty convinced that this is as close to a panacea diet as you can get. If you have any type of chronic problem or illness you owe it to yourself to try it out for an extended period. Besides personal anecdotal testimonies you can read and listen to experiences of Paleomedicina institute in Hungary which to my knowledge so far the only medical facility in the world that uses this type of diet to heal/control various illnesses. You can read their case reports that they published in various journals from eliminating type I diabetes to controlling serious cancers cases with their variants of this diet.
The Fat of the Land by Vilhjalmur Stefansson should be your first reading stop if you are interested in this way of eating, it has convinced me to give it a try as it gave me sufficient evidence not just of short health benefits but of the long term sustainability of the diet.